It was March 31, the emotion-filled day when Ivy League universities posted their decisions online. And Augusta Uwamanzu-Nna, a senior at Elmont Memorial High School, became the second student there to pull off an exceedingly rare feat: She swept all eight.

She screamed. Then she cried.

“It’s so surreal,” Ms. Uwamanzu-Nna, 17, said on Wednesday. “It’s still hard to actually believe that this has happened to me.”

The accomplishment is all the more remarkable given the increasingly fierce competition that has driven down acceptance rates at selective universities for years. Harvard’s, for example, was 5.2 percent this year, down from 9.3 percent in 2006. News reports suggest that justa few students pull off a sweep each year.

What’s more, Ms. Uwamanzu-Nna (pronounced oo-wah-man-ZOO-nah) is just the latest student from her school to do it. In 2015, Harold Ekeh drew national headlines when he was accepted to 13 universities, including all eight Ivies.

Image

Ms. Uwamanzu-Nna got into 12 colleges in all, including eight Ivies.

Elmont officials said Mr. Ekeh, now a freshman at Yale, had been a huge inspiration to other students. He is also close friends with Ms. Uwamanzu-Nna.

She proposed the idea of applying to all eight universities to her counselor at the start of the school year.

“I actually encouraged her,” the counselor, Sanju Liclican, said, “because I knew she could do it.”

Many admissions advisers, however, discourage the practice.

Dean Skarlis, president of the counseling service College Advisor of New York, said that even exceptional students were better off applying to only a few Ivy League schools, along with several “probables” and a couple of safety schools.

“Just because, with their acceptance rates between 4 and 12 percent, if you put all those eggs in those baskets — most kids don’t get any if they apply,” he said. “It’s extremely competitive.”

Ms. Uwamanzu-Nna, however, had a lot going for her — a better-than-perfect grade point average, made possible by taking the hardest classes, and the distinctions of being both valedictorian of her class and a finalist in the prestigious Intel Science Talent Search.

Her scientific pedigree most likely represented a crucial advantage since universities are seeking to usher more women into the sciences, said Kat Cohen, the chief executive of the admissions counseling service IvyWise.

Ms. Uwamanzu-Nna also presented a compelling personal story. As the daughter of Nigerian emigrants, she shared something with many of the Ivy League sweepers in recent years. They tend to have immigrant backgrounds.

American universities, especially the Ivies, have been placing greater emphasis on diversifying their student populations, admissions counselors say.

“They are very concerned about racial and ethnic diversity,” Mr. Skarlis said. “They would rather have the Latino kid from the Bronx who has overcome something significant in his life, rather than the upper-middle-class or more affluent white student.”

Ms. Uwamanzu-Nna said she was shocked to get into so many colleges: In addition to the Ivies, she won admission to Johns Hopkins University, the Massachusetts Institute of Technology, New York University and the Rensselaer Polytechnic Institute.

If Ms. Uwamanzu-Nna is favoring any one in particular, she isn’t telling. She said she wanted to pursue biochemistry and environmental science, and planned to research the 12 universities and visit their campuses soon.